Analytical investigation in the seismic response of segmental hollow core bridge piers

Abstract Segmental precast post-tensioned (SPPT) bridge piers are a promising alternative to conventional cast-in-place bridge substructures due to their rapid construction and enhanced seismic performance. In this system, the footing, column segments, and cap beam are prefabricated and assembled using unbonded post-tensioned (PT) strands extending continuously throughout the pier. The unbonded PT strands provide excellent self-centering capability, thereby reducing seismic damage and residual displacement. However, the system has limited hysteretic energy dissipation. To address this limitation, bonded mild steel energy-dissipating (ED) bars are installed across the segment joints. Additional unbonded lengths are provided to delay low-cycle fatigue damage and prevent premature fracture of the ED bars. Three-dimensional finite element models were developed and validated against experimental results reported in the literature. The validated models were then used to investigate the seismic behavior of SPPT bridge piers under cyclic loading. The studied parameters included the number of column segments, the initial stress, orientation, and ratio of PT strands, as well as the ratio and additional unbonded length of ED bars. The results provide design recommendations for improving the seismic performance of SPPT bridge piers.